This invention relates to an injection molding machine and, more particularly, to a nozzle touch plate for use in the injection molding machine against which the injection nozzle of the machine touches at the time when the type or color of the resin is changed.
In a prior art injection molding machine, at the time of changing the type or color of the resin the injection nozzle is brought into contact with a metal mold for applying the back pressure in a heating cylinder. This method, however, involves the following problems.
(1) It is necessary to set the metal mold into the injection machine.
(2) A long operation time is necessary for repeating an injection operation (purging) and retraction of the injection nozzle for the purpose of nozzle touch and changing the type or color of the resin.
(3) Since during the purging operation the metal mold is used, it is impossible to change the metal mold.
(4) Since the metal mold is used, and the resin is injected into the mold, it is necessary to remove the resin from the metal mold.
(5) Depending upon the types of the metal mold and the resin, in a certain case it is impossible to apply a high back pressure.